80 
posterior tooth of the right valve the shorter, 
notched ; muscular impressions round. 
Syn. Cultellus cultellatus, S. V. Wood in Ann. and 
Mag. Nat. Hist. v. vi.245. 
A. very fragile and rare shell, differing in its oval shape as 
well as in the form of the hinge-teeth from C. affi?iis, from 
Solen tenuis of Philippi and Nyst, and Solen jragilis of La- 
marck, to any one of which it might possibly be referred. 
We are indebted to S. V. Wood, Esq., for the use of 
the specimens figured. The species occurs in coralline 
Crag of Sutton and the red Crag of Walton Naze. 
CULTELLUS affinis. 
Spec. Char. Transversely elongated with round- 
ed extremities, compressed, shining, obscurely 
radiated, upper and basal edges nearly straight 
and parallel, the anterior margin slightly re- 
flected and thickened within. Width three 
times the length. Posterior hinge-tooth in 
the right valve the larger and flattened. 
Syn. Solen affinis. Min. Con. t. 3. 
The larger figures upon this plate are from fine specimens 
discovered in the Barton Cliff by Mr. F. E. Edwards; in 
them the edges are so much more parallel than in the 
Highgate (young?) shells, that they have been thought a di- 
stinct species, and have received the manuscript name of 
Bartonensis; however, the lines of growth near the beaks 
show that the young shell was more elliptical, and there- 
fore I must suppose them to be all one species. Small in- 
dividuals have been found at Bognor. The teeth of the 
hinge distinguish it from Cultellus cultellatus. 
